fix(tests): patch head_bucket function correctly

[sergargar]

Context

Tests for the check cloudfront_distributions_s3_origin_non_existent_bucket were failing because of mocking the head_bucket function incorrectly.

Description

By specifically patching s3_client._head_bucket within the context of each test, we're ensuring that it returns the correct values.

Checklist

• Are there new checks included in this PR? Yes / No
  • If so, do we need to update permissions for the provider? Please review this carefully.
• Review if the code is being covered by tests.
• Review if code is being documented following this specification https://github.com/google/styleguide/blob/gh-pages/pyguide.md#38-comments-and-docstrings
• Review if backport is needed.

License

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.14%. Comparing base (3db541a) to head (9c86f34).
Report is 4 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5246   +/-   ##
=======================================
  Coverage   89.13%   89.14%           
=======================================
  Files         988      989    +1     
  Lines       30374    30397   +23     
=======================================
+ Hits        27075    27097   +22     
- Misses       3299     3300    +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[puchy22]

LGTM! 👍